So you've got a sound card or motherboard with either a coaxial or optical digital-out plug. You've connected it to your fancy speakers or home theatre receiver, but something's not quite right... have you noticed that you hear sounds from your favourite 3D games in the front speakers only, or you hear the same stereo sounds from all 4, 5, 6 or 7.1 speakers? Well my friend, you've just fallen into possibly the most common trapping of PC digital sound... First, a little technical info. I won't spend too much time on the fine details, I'll try and sum it up as best as I can. Analogue vs. Digital: Analogue sound travels as waves of electricity that are subject to interference from nearby electronic equipment. Digital overcomes this by encoding the sound into zeros and ones before sending it over the cables, much like the screech of an old modem when you pick up the phone (we don't understand it, but computers can process it). Digital is tolerant to interference, but excessive interference will stop the sound entirely, you either get a perfect signal or none at all. Digital Formats: When audio is encoded digitally, the equipment at both ends needs to be able to recognise the codes of zeros and ones. That means talking in the same "language", also known as "format" or "standard". There are more, but only three digital formats are in mainstream home sound use. Those being PCM, DTS and Dolby Digital (also known as AC3). For more detailed information on sound formats, try this thread on the Audio Visual forum. Encode and Decode: In the context of this thread, these two terms relate to converting sounds to and from a digital signal. Your sound card ENCODEs a digital signal in one of the above formats, while the speaker system (or home theatre receiver) at the other end DECODEs that signal. Anyway, on with the story... The digital format is really where this problem lies. Your sound card is sending your game's sound in PCM format, and chances are there's nothing you can do about it. Every sound card with a digital plug is able to encode PCM. PCM is uncompressed, it's fast, simple and cheap to encode and used in everything from old digital telephone systems, to Compact Discs (Wikipedia). The PCM format supports 2 channels of sound only, that is, stereo. When you play a game on your computer, your sound card is still making a PCM signal and sending that over the digital cable, so you will only ever get LEFT and RIGHT. I'll just repeat that last point by itself for emphasis... When you play a game on your computer, your sound card is still making a PCM signal and sending that over the digital cable, so you will only ever get LEFT and RIGHT. Right about now, some of you reading this will be thinking something like "but when I play a DVD on my computer I get my surround sound just fine", and you're correct. In this case the people producing the DVD have already ENCODEd either a DTS or Dolby Digital (AC3) signal and stored it on the DVD. Your sound card is simply copying that signal and sending it straight over the digital cable without doing any processing of its own (the same applies to HDTV cards I think, except the AC3 signal is coming, already encoded, from the television broadcast). So, what can you do about it? Well, sorry folks, but the only way you're going to get proper surround sound from your 3D games with your current sound card is to hook up your speakers using all those seperate analogue plugs you probably have at the back of your computer. There are alternative solutions however... The nForce2 motherboard chipset with "Soundstorm" on-board sound has a feature that allows it to ENCODE 3D game sound into a Dolby Digital signal on-the-fly, instead of relying on PCM stereo The HDA Digital X-Mystique 7.1 sound card (plugs into any standard PCI slot) also has a similar feature, but comes with the advantage of not being a number of years out of date Creative have a product called the Home Theater Connect DTS-610, which allows you to encode six channels of analogue sound into a DTS signal on the fly, however this means you still have to run a bunch of analogue cables from your PC sound card to the DTS-610 box, and then run a digital cable from that to your speakers / hifi Well I hope that dispells some misconceptions that people have and helps you judge which product to buy. I'll open the floor to corrections, suggestions and more in-depth discussion, but wanted to try and keep this first post as simple as possible without losing too much useful info. I haven't even spell / grammar checked it yet Something like this should be stickied here IMHO. If not this post specifically, then I hope I've at least given something that others can link to and say 'here, read this'.